Telephone-exchange system.



J. N. REYNOLDS.

TEL'EPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR. 4. 19l5.

WIT/Maw 2* Jo/m $1M fiy Patented Mar. 20, 1917.

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JOHN NEWBERRY REYNOLDS, OF GREENWICH, CONNECTICUT, ASSIGNOR, BY MESNE ASSIGNMENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

TELEPHGNE-EXCHANGE SYSTEM.

Patented M ar. 20, 1917.

Application filed March 4, 1915. Serial No. 11,955.

To all whom it may concern Be it known that 1, Jenn NEWBERRY Enrzvoiios, citizen of the United States, IB SIding at Greenwich, in the county of Fan-held and State of Connecticut, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, and has to do more particularly with line testing in telephone exchange systems utilizing automatic switches for connecting with the calling and called lines to build up connections. The 0l3160t of the invention is to provide effective and simplified means associated with the hues and switches for testing the lines at a slngle test contact on each switch for each line.

In automatic switches of the character referred to, there is usually circuit known as the test circuit thereof including a test brush on the movable portion of such switch,

which tests on the one hand the calling or non-calling condition of the line, or, on the other hand, the lousy or idle condition of the line, depending whether such automatic switch is a line finder switch, trunk finder switch or a connector.

According to one feature of this invention, the normally electrically separated calling and answering test contacts of a subscribers line are, upon the initiation of a call. on said line, connected together under the control of the line relay. Upon the clo sure of said connection the electrical potential on multiples of said terminals is reduced to render the subscribers line inaccessible for other line finders and for connector switches through said terminals.

Another feature of this invention calls for a cut-off relay, the coil of which is normally connected to the calling multiple test contacts of a subscribers line and normally disconnected from the answering multiple test contacts of said line. Upon the energization of a line relay individual to said subscribers line, said open connection is closed and the line rendered busy on both sets of terminals.

According to still anotherfeature of this invention, the coils of both the cut-off and the line relay are included in the test circuit.

Still another feature of this invention relates to the provision of a test circuit for a terminal bank having on one side multiple test contacts adapted to be engaged by a line finder, and on the other side multiple test contacts adapted to be engaged by a connector or selector switch.

()ther novel and useful features of this invention will more fully appear from the following detailed description of the system and the appended claims.

The drawing represents a diagrammatic view of an automatic telephone exchange, only so much being shown of the circuits and apparatus employed therein as is necessary for the understanding of the present invention.

Although this invention is disclosed as embodied in an automatic telephone system, it will be apparent that it may be equally well applicable to systems of widely varying character, such as semi-automatic telephone systems, manual telephone systems, etc. Nor is this invention limited to any specific types of switches, but is readily applicable, as will be understood by those skilled in the art, to switches widely varying in type.

Subscriber 1 desiring to initiate a call removes his receiver from the switchhook, closing thereby an energizing circuit for line relay :2 and group relay 3 from grounded battery i through the coil of relay 3, lefthand winding of relay 2, inner armature and back contact of cut-off relay 5, line 6, substation, line 7, and. back contact and outer armature of relay 5 to earth and back to battery.

The energization of group-relay 3 causes line finder 10 to hunt for the calling subscribers line 6, 7. Preferably line finder switches of the so-called panel type are employed. The contact banks or panels are divided into sections, one of such sections being shown in the drawings. Each section comprises terminal strips 11, 12, 13 and 18, and a brush 14, 15 and 16 respectively is provided for each of the first three strips of terminals, the sets of brushes serving a given section being spirally arranged upon a common carrier (not shown). A row of terminals is provided on each side of strips 11 and 12, those on the right-hand side are adapted to be engaged by brushes 14:, 15 and 16 of line finder 10 and will hereinafter be referred to as answering terminals or conagain energized.

tacts (being engaged in response to the initiation of a call), and those on the lefthand side are adapted to be engaged by the brushes of a connector switch and will hereinafter be referred to as calling terminals or contacts (being engaged only when subscriber 1 is called). Section 13 carries n1ultiple terminals, but only on its right-hand side. These are the multiple answering test contacts of the subscribers lines. Section 13 carries multiple terminals, but only on its left-hand side. These are the multiple calling test contacts of the subscribers lines. Each carrier may be given a rotary movoment by means of an clectroimignet 17 to position a predetermined set oi. brushes in operatire relation to the terminal strips of its section, and a vertical movement by means of electromagnot 18 to cause said brushes to wipe over the terminals of said section.

Each group of lines, multiply connected to terminals on the left and right hand side (or calling and answering terminals) of strips 11 and 12 of the respective sections, has a brush carrier normally apportioned to it with one of its sets of brushes in operative relation to the answering multiples of said terminals. By virtue of this arrangement, upon the initiation of a call in any group, a brush of the carrier apportioned thereto will be in position to wipe over the answering terminals in search of the calling line, no rotary movement of the carrier being necessary.

Supposing, however, that the brush carrier apportioned to the group into which subscriber 1 belongs is busy; upon the energization of group relay 3, a circuit is closed from ground through outer armature and back contact oi. relay 3, conductor 19, wiper 20, conductor 21, armature and back contact of magnet 22, armature and back contact of test relay 23, arm atures and back contacts of magnets 17 and 18, conductor 24, wiper 25, and winding of magnet 17 to grounded battery 26. Magnet 17 by attracting its armature interrupts its own circuit and thereby is successively de'energized and The operation of magnet 17 is similar to that of a buzzer. Magnet 17 rotates th brush carrier of line finder 10 until an arm 27 provided at the top of said brush carrier and adapted to wipe over a circle of contacts 28, reaches a contact in which conductor 29 terminates. In this instance a circuit is closed from ground through inner armature and front contact of relay 3, conductor 29, arm 27, conductor 30, wiper 31, conductor 32 and winding of magnet 22 to grounded battery 33. Magnet 22 becomes energized and causes wipers 20, 25, 31, 34: and mounted on a common shaft (not shown) to move from their first position into their second position. When wiper 31 leaves its first position, magnet 22 becomes deenergized and said wipers will be arrested in their second position.

)Vhen magnet 22 became energized it attracted its armature and opened thereby the circuit of magnet 17. Magnet 17 being deenergized the brush carrier is arrested with brushes 1 1, 15 and 16 at the bottom of terminal strips 11, 12 and 13 respectively.

1V ipers 20 and 25 being in their second position, a circuit is closed from ground through outer ari ature and front contact of relay 3, conductor 19, wiper 20, conductor 21, armature and back contact of magnet 22, armature and back contact of relay 23, back contacts and armatin'es of magnets 17 and 1S, conductor 24:, wiper 25, and winding oi magnet 13 to grounded battery 26. Magnet 18 causes the carrier to travel with brushes 1d, 15, 16 and arm 27 in a vertical direction in contact with the terminals of strips 11, 12 and 13 respectively, the operation of this magnet being similar to that of magnet 17.

Brushes 1-il-, 15, 16 continue their travel. until test-brush 16 reaches test terminal 40 of strip 13. A test circuit is now established from grounded battery 'Il-1 through the coil of cut-oft relay 5, conductor 12, front contact, armature and right hand winding of line relay 2, conductor 43, test terminal 40, brush 16, wiper 31 (in position two) conductor 4: 1; and winding of test relay 23 to ground and back to battery. Test relay 23 and cutoff relay 5 become energized and thereby the potential on test terminal a0 and on the answering multiple test terminals lO,'etc., i. 0., the terminals to which test conductor -13 of the calling subscribers line is multipled, is reduced in the well known manner. Thereby it is prevented that another test relay individual to another line finder becomes energized when the test brush of said finder makes contact with one of said answering multiple test terminals.

Upon the energization of relay 23, brushes 14-16 are arrested on terminals 415, 4:6 and 40 respectively, the circuit of magnet 18 being opened at the armature and back con tact of relay 23. Relay 23 closes also a circuit from grounded battery 33, through the coil of magnet 22, conductor 32, front contact and armature of relay 23, back contact and armature of magnet 22, conductor 21, wiper 20 and front contactand armature of relay 3 to ground. Magnet 22 becomes energized and allows wipers 20, 25, 31, 34 and 35 to move into their third position, the circuit of said magnet being opened soon as wiper 20 leaves its second position. hen wiper 31 leaves its second position, the circuit of test relay 23 is also opened and the earth connection for the test circuit is supplied now directly through wiper 31 t in position three).

Cut-0H relay 5 upon energization, at-

tracts its armatures, opening thereby the original energizing circuit of line relay 2 and group relay 3. Relay 3 becomes denergized, relay 2, however, remains energized, its right hand winding being included in the above traced test circuit. Should a new call be initiated in this group, relay 3 would again become energized, but in this case, the call would be extended to another line finder through conductor 19, wiper 20 (in position three), conductor 19, wiper 20, etc.

The subscribers line is extended through line terminals 17, 48 and answering termi nals 45, 46 of terminal strips 11 and. 12, brushes ll, 15 of line finder 10, wipers 31, 35 to brushes 49, 50 of a selector switch 51 and the subscriber may proceed now to control the setting of said selector switch in the well known manner by operating his impulse sending device 52.

After the conversation is terminated, the

v parties hang up their receivers 011 the switchhooks and the switches employed in the building up of the connection are restored to their normal position in the well known manner. Then brush 16 of line finder 10 leaves contact 40 the test circuit will be broken, relays 5 and 2 deenergized and thereby the busy test potential removed from the answering and calling multiple test terminals.

If another subscriber desires to obtain a connection to subscriber 1, he sets brushes 53, 54 and 55 of a connector switch on multiple calling terminals 58, 59 and 60 of the line terminals a7, 48 and 61 of subscriber 1, provided on terminal sections 11, 12 and 13 respectively.

In case subscriber 1 is idle, a test circuit is closed for the test relay 63 of said connector from grounded battery 41, through the winding "of cut-off relay 5, conductor (34:, line test terminal 61, calling multiple test terminal 60, brush 55 and winding of relay 63 to ground and back to battery. Relays 5 and 63 become energized and the latter causes the stopping of brushes 53 and 5a of terminals 58 and 59. Subscriber 1 will now be signaled and the two parties may enter into conversation in the well known manner.

Due to the closure of the above traced test circuit, the electrical potential on the other calling multiple test terminals 2'. 6., the terminals to which conductor 6% is multipled is reduced. Should now another subscriber attempt to obtain a connection with subscriber 1, the test relay individual. to his connector switch will not receive suflicient current through a multiple of test terminals of strip 13 of the selected section. The test relay remaining deenergized brushes 53, 54: are restored to normal and the calling subscriber is informed in the well known mannerthat the called subscriber is busy.

In case of an attempted connection to subscriber 1 after this subscriber initiated a call and is therefore busy as a calling subscriber, the brushes of the connector will be v restored to normal and busy signal operated in the same manner as in the aforementioned case. In this case the test potential on the calling multiple test terminals is reduced and thereby test relay 63 cannot become energized, due to the fact that a test circuit is closed through thewindings of cut-off relay 5 and line relay 2 as described in connection with the initiation of a call by subscriber 1..

lVhat is claimed is:

1. In a telephone exchange system, a telephone line, a line and a cut-oil relay therefor, answering and calling multiple test contacts for said line, a connection between said test contacts established through a contact of said line relay, and a holding circuit for said line relay including its contact and one of said multiple test contacts.

2. In a telephone exchange system, a telephone line, a double wound line relay and a cut-off relay for said line, answering and calling multiple test contacts for said line, a line finder for engaging said answering contact, a start relay for said line finder, a circuit controlled over said line and including a contact of said cut-off relay, one Winding of the line relay, and the winding of said start relay, and a holding circuit for said line relay including the answering test contact and the other winding and a contact of said line relay.

3. In a telephone system, the combination with a telephone line, of multiple calling test contacts for said line and multiple answering test contacts for said line normally electrically separated from the multiple calling test contacts thereof, a cut-off relay for the line having its coil permanently connected with the multiple calling test contacts of the line, and a line relay for the line having a. coil and a pair of normally open contacts included. in a connection between the coil of said cut-off relay and the answering multiple test contact of said line by the actuation of the line relay.

4:. In a telephone system, the combinatio with a telephone line, of multiple line and test terminals therefor, a set of line finder contacts and means to move them into contact with successive stationary line terminals, a line relay for the line adapted by its actuation to place calling test potential upon one of the multiple contacts for said line, and a cut-off relay for the line having its coil included in the test circuit by the actuation of said line relay, said test circuit also including a winding of said line relay.

5. In a telephone system, the combination with a telephone line, of a terminal bank, multiple contacts on one side of said bank through which connection may be established with said line as a called line, multiple contacts on the other side of said bank through which connection may be established with said line as a calling line, normally electrically separated multiple test contacts, one on each side oi? said terminal bank, a li e relay for the line, and contacts on said line relay for connecting said test multiples together when the line relay is first actuated.

(3. In a telephone system, the combination with a telephone line, of a line and a cut-off relay for said line, a terminal bank, answering multiple test contacts for said line on one side of said bank, calling multiple test contacts for said line on the other side of said bank, a connection ixtending from the calling multiple test contact of said line to the coil of said cut-oil relay, and a connection extended from the answering mul tiple test contact oi. said line to the coil of said cut-o'fii' relay by the actuation of the line relay of said line.

7. In a telephone system, the combination with a telephone line, calling multiple test contacts for said line on one side of said ank, answering multiple test contacts for said line on the other side of said bank normally electrically separated from said calling test contacts, a cut-off relay for the line havingits coil permanently connected with the calling multiple test contacts of the line, and a line relay for the line having a coil and a pair of normally open contacts included in a connection between the coil of said cut-oi? relay and the answering; multiple test contact of said line by the actuation of said line relay.

8. In a telephone system, the combination with a telephone line, of a terminal bank, multiple line terminals on both sides, an swering test terminals on one side and calling test terminals on the other side of said bank for said line, a set of line finder contacts and means to move them into contact with successive stationary line terminals, a line relay for the line adapted by its actuation to place calling test potential upon one of the multiple terminals for said line, and a cut-oil" relay for the line having its coil included in the test circuit by the actuation of said line relay, said test circuit also including a winding of said line relay.

In witness whereof, I hereunto subscribe my name this 2nd day of iii arch A. 1)., 1915.

JOHN NllWBllltltY REYNOLDS.

\Vitnesses E. EDLER, K. L. STAI-IL.

(topics of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, I). G. 

